Catalytic Flame Synthesis of Carbon Nanotubes

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Public AbstractAward CTS-0522556PI: Stephen D. TseCatalytic Flame Synthesis of Carbon NanotubesCarbon nanotubes (CNTs) define a new class of engineering materials with remarkable physical and electromagnetic properties, with a myriad of potential applications, including high-strength polymers, copolymers, composites, ceramics, moldable forms, molecular electronics and nano-scale machines, superconductors, delivery systems of bio-molecules to cells, fuel storage and batteries, flat-panel displays, and computer memory devices. Although various techniques have been developed for the production of CNTs, including pulsed arc discharge, pulsed laser ablation, and thermal chemical-vapor deposition, they are not readily or economically scalable for large-scale applications. Combustion synthesis of materials has demonstrated a history of scalability and offers the potential for continuous, efficient, high-volume production, without the need for expensive starting materials. As such, the objective of the proposed research program is to increase fundamental understanding of the mechanisms of catalytic CNT formation and growth in electrically-assisted flames, and utilization of that understanding to define process conditions that enable high-rate and high-purity synthesis of CNTs with prescribed characteristics (e.g. single- or multi-walled, diameter, helicity). The experiments are conducted using strategic aerodynamic flow fields, i.e. flat-flame stagnation-point (premixed) and flat-flame counterflow (non-premixed), to characterize the effects of fuel composition, flame temperature, inert addition, hydrogen addition, oxygen concentration, strain rate, and other controllable process parameters on CNT properties. The influence of the nature as well as the content of the transition metal (Ni, Fe, and Co) in the substrates on the yield and the quality of the CNTs formed will be investigated, along with the influence of electric fields in controlling CNT purity, alignment, helicity, and growth rate. Advanced laser-based diagnostics including spontaneous Raman spectroscopy, laser-induced fluorescence, and tunable diode laser absorption spectroscopy are employed to determine the local gas-phase chemical species concentrations and temperatures at the specific regions of CNT formation. The CNT material properties are characterized using electron microscopy, atomic force microscopy, and surface Raman spectroscopy. The research and experimental facility are incorporated into the curriculum on nanomaterials science and engineering. The involvement of underrepresented minorities and women in engineering is increased by supporting undergraduate research as part of the Douglass Project for Rutgers Women in Math, Science, and Engineering. The training of students (at high school, undergraduate, and graduate level) for the high-technology workforce is promoted by partnering with industry, state, and Center for Nanomaterials Research.